Isn't it right to say "isn't it" instead of "is it"?
Answer from a Native speaker
"Isn't it" is an affirmative statement that is used to agree with something or present something in a way where someone could not disagree. On the other hand, "is it" is not an affirmative statement, but instead is used to question what someone says. In this case, he says "is it" to question the statement "this is life and death" and to express doubt and possibly disagreement towards this statement. So since his purpose here is to question the statement, "is it" is correct. Ex: The weather today is nice, isn't it? Ex: A: It's hot outside. B: Is it?